<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      .box {
        display: flex;
        /* 将主轴设置Y轴 */
        flex-direction: column;
        justify-content: center;
        align-items: center;
        width: 100px;
        height: 100px;
        background-color: pink;
      }
    </style>
  </head>
  <body>
    <div class="box">
      <a href="#">aaaa</a>
      <span>bbbb</span>
    </div>
  </body>
</html>
